Here's the wheel from the side. An improvement to be made here is to eliminate the sharp corners on the rail on top of the tray, it digs into my left leg and I have to place a towel between it and my leg. The seat is covered with a thick layer of foam and a towel to be a little less uncomfortable on the bum. I initially left the angled crossbrace off the wheel but added it later for a bit more stability. Notice that it's not stained...when I bolted it in to check the fit I snapped the head off the bolt....so it's permanent now.
This is the chain attaching the treadle to the tray. On my version I resolved to use bearings everywhere something needed to move, this makes everything a little smoother and I never have to oil/grease anything. The bearing is called a swivel bearing, it spins like a regular bearing but also swivels up to 60 degrees. They're not too expensive, I got mine from Mcmaster-Carr.
Another larger swivel bearing, this allows the treadle and the block to move up and down on the shaft as the treadle arcs, it also eliminates some of the clickity-clack noise(that may be a good or bad thing depending on your level of nostalgia...)The block is attached to the shaft with a piece of Teflon...it's super smooth and doesn't need to fussed with like leather that the plans call for. I'd like to cover this with leather for aesthetic reasons though. The extra hole in the treadle arm is because I misplaced the first hole...oops. The piece underneath the block is called a shaft collar, again from mcmaster. It keeps the block from sliding down the shaft and binding.
This is where the treadle attaches to the leg, the plans call for this beefy metal contraption which I didn't have the proper tools to fabricate so I came up with this. The threaded rod makes it adjustable. Note the use of a swivel bearing again, are you sensing a theme? It works but it's kinda ugly though.
The wheelhead is stripped off an old kickwheel. It's a 10" wheel and the holes closer together were already there, I drilled the wider ones for my bats.
This is the bottome of the wheel, a taper fits the shaft onto the wheel and there's a little notch to keep it from spinning on the shaft. In the tray I glued a short piece of pvc pipe to keep slop from falling through the hole and onto the bearing. Wheelheads are expensive, I got this old kickwheel for cheaper than a new wheelhead.
The tray sits loose on the frame for easy removal, it's held in place with pegs on the front corners and the edge of the seat. Here you can also see how the frame fits together. The T shape is mortised, glued and pegged. The angled braces are bolted in and removable, The wheel is 32" wide on the shortest side so making those guys removable makes it easier to get through tight doors.
Here is the top shaft bearing, bolted to the underside of the frame. These have to be periodically oiled, I got the pair of them off ebay for cheap. They are 1" bearings.
The bottom bearing is mortised into the frame about 3/4" and sits directly under the flywheel.
The angled braces fit into mortises in the legs and are then bolted. The braces have threaded inserts in the ends that the bolts thread into, I thought this was a clever idea but it doesn't hold as tight as what's in the plans. The front legs and top T braces are finished 2.5X3". The bottom T brace and the rear leg are 3X3". The bottom brace holds a lot of weight, and the rear leg has all the braces tying into it so I wanted them a little beefier. The plans call for everything to be 3x3" though but I couldn't get that much thick stock locally.